Screw propeller with resilient blade



Dec. 27, 1955 M. K. BRANNON SCREW PROPELLER WITH RESILIENT BLADE Filed Jan. 15, 1954 Milton K. Brannon IN V EN TOR. M t

BY film United States Patent O SCREW PROPELLER WITH RESILIENT BLADE Milton K. Brannon, Patterson, La. Application January 15, 1954, Serial No. 404,359

2 Claims. (Cl. 179-156) The present invention relates to an improved screw propeller which is suitable and well adapted for use in conjunction with propeller-driven conveyances, that is especially well intended and therefore appropriate for use on powered boats and analogous watercraft.

More specifically, the invention has to do with a propeller which is expressly designed and therefore suitably adapted to encounter weeds, underwater snags, water lilies and other debris and is substantially self-cleaning and therefore will not be fouled and incapacitated by way thereof.

Another and equally important objective is to provide a propeller having rubber or equivalent blade means which is yieldable and compensating in character and will prevent the propeller from becoming damaged or rendered inoperative upon striking relatively immovable objects such as logs, rocks and the like.

Another object has to do with a yieldable propeller, the design of which oifers a minimum of frictional resistance to the water and ensures proper and reliable transmission of required forces and torque, whereby to promote operation which is comparable with any other type of rigid metal or equivalent propeller in the so-called screw propeller category.

Brifiy summarized, a preferred embodiment of the invention has to do with a propeller along the lines stated which is characterized by a rigid tubular driven shaft for driving connection to a powered drive shaft having an integrated propulsion blade wound around the same and ranging from end to end of the shaft, said blade increasing in thickness toward its junctural connection with the complemental surface of the shaft, said blade being characterized by two complete convolutions and having its thickest component situated between the respective ends of said shaft and the remaining forwardly and rearwardly, advancing components gradually decreasing in thickness and width dimensions toward and to the respective ends of said shaft.

Then, too, novelty is predicated on the structure stated wherein the blade has a full turn convolution at the central portion midway between the respective ends of the shaft and half-turn complemental convolutions at the respective ends thus providing a structural adaptation which, in side elevation, represents what may be described as a double-pointed screw and which lends itself to operation either clockwise or counter-clockwise and is highly adapted for movement both forwardly and rearwardly while producing requisite thrust and stability in either direction and is, in addition, rendered substantially self-clearing of debris.

Further novelty is predicated on blade means which is constructed of molded rubber which is interiorly reinforced by way of rubberized fabric means which may be described as a foundational carcass, the over-all blade being thus characterized by a tubular hub which encases the metal shaft and blade forming convolutions which spirally wind and advance around the hub from end to end, the convolutions each being laminated and the outer e r? Ice Patented Dec. 27, 1955 laminations being of rubber and the intervening lamination of reinforcing rubberized fabric or an equivalent material.

Other objects, features and advantages will become more readily apparent from the following description and the accompanying sheet of illustrative drawings.

In the drawings, wherein like numerals are employed to designate like parts throughout the views:

Figure l is a side elevation of a screw propeller constructed in accordance with the principles of the present invention;

Figure 2 is an end view of the same observing, for example, the structure of Figure 1 in a direction from left to right;

Figure 3 is a section on the vertical line 3-3 of Figure 1, looking in the direction of the arrows; and

Figure 4 is an elevational view of the aforementioned open-ended tubular flanged driven shaft.

With reference first to Figure 4, the stated shaft is denoted by the numeral 6 and actually provides the core of the propeller and it is. made of rust-proof metal or suitable commercial plastics or an equivalent noncorrodible material and is generally cylindrical in crosssection and of uniform diameter from end to end, but may have a tapered bore if desired. On the interior of the bore there is a keyway 8, as shown, for example, in Figures 2 and 3, whereby the same may be mounted on a powered drive shaft on a boat or the like (not shown). The shaft has outstanding flanges 10 and 12 at its respective ends. The peripheral surface is denoted at 14 and this is provided with a multiplicity of suitably spread or arranged nodule-like projections or embossments, as at 16.

The fabricated reinforced rubber propeller or blade means is a composite rubber and rubberized fabric adaptation. It may be said to comprise a central hub portion which encases the shaft 6 and spiralling blade components. The hub portion embodies an inner rubber lamination of sleeve-like form which is denoted at 18 and which appears in Figure 3, and this is surrounded by the intervening reinforcing fabric layer or lamination 20 which latter is, in turn, surrounded by a sleeve-like outer rubber ply or lamination 22. The hub extends between the flanges 10 and 12 and the inner rubber lamination 18 is securely anchored by the embossments 16, as is obvious. All components of the blade means are the same in that there is an inner fabric reinforcing ply or lamination 24 with complemental rubber plies or laminations 26 and 28 encasing or jacketing the same. A section through the blade shows that it is tapered to an approximate relatively thin outer edge portion, as at 30.

One end of the blade, as at 32 at the left in Figure 1, begins inwardly of the adjacent flange 10 from what may be called a zero or starting point, and, as it clear, it radiates outwardly and advances along a spiralling half-turn course until it reaches a point which is diametrically opposite the zero point, that is, a distance of approximately 180, the point which is denoted by the numeral 34 in Figure 2. This designates or identifies the maximum outside diameter or circumference, and the blade continues in its encircling spiral travel while retaining the then established maximum circumference until one 360 full turn is completed. It then regresses or travels in a reverse manner and radiates or travels inwardly while following a second spiralling 180 half-turn course toward the other, or right hand, end of the shaft where it merges into the latter and terminates at what may be called the zero point 36 which is spaced longitudinally from the point 32 but is situated on the same side of the hub, and the over-all blade thus defines two complete convolutions or turns. The

half-portions 38 and 40 go to make up what is equivalent to one turn, and the intervening complemental larger half-portions 42 and 44 go to make up the complete median turn or convolution, which is generally denoted by the numeral 46 in Figure 1. It is to be noted that the thickest portion of the blade will be at the exact center, as may be conveniently denoted at the point 48 and gradually becomes thinner from there to the left and right, that is, the respective starting and terminal points 32 and 36, respectively.

it is believed that the propeller herein revealed is simple, economical and practical and will meet the respective requirements and needs of manufacturers and users, and will provide adequate rigidity to ensure suitable thrust while at the same time provides enough resiliency and flexibility that it will deflect under excessive loads, such as striking a submerged rock or becoming fouled with weeds. Of course, the rubber will be appropriate softness and flexibility consistent with having the capacity to transmit the desired forces and torque, and will reduce noise to a minimum.

The pressure of the reaction developed between the water and the spiralling surfaces of the blades when revolved in one direction will serve to drive a vessel forward and to ensure maximum efficiency of propulsion, especially because of the self-clearing and yieldable compensating factors which minimize damage and break age under all but abnormal operating conditions.

From the foregoing, the construction and operation of the device will be readily understood and further explanation is believed to be unnecessary. However, since numerous modifications and changes will readily occur to those skilled in the art, it is not desired to limit the invention to the exact construction shown and described, and accordingly, all suitable modifications and equivalents may be resorted to, falling within the scope of the appended claims.

What is claimed as new is as follows:

1. A screw propeller comprising a rigid tubular openended shaft having circular outstanding integral flanges at its respective ends and nodule-like embossments along its outer peripheral surface, a composite tubular hub encasing said peripheral surface between said flanges, said hub embodying an inner sleeve-like lamination of rubber bonded to said surface with the aid of said embossments, an outer concentric sleeve-like lamination also of rubber, and an intervening complemental sleeve-like reinforcing lamination of rubberized fabric securing and uniting the several larninations into an entity, and a a blade integral with said hub and having convolutions spirally winding and gradually advancing from end-toend of said hub, each convolution being laminated and embodying an inner lamination of reinforced rubberized fabric and an outer lamination of rubber encasing said i=1) inner lamination, said inner lamination being united with, constituting an extension of, and radiating from the aforementioned intervening sleeve-like lamination, and said outer encasing lamination being united with, constituting a similar extension of, and radiating from 13 the aforementioned outer sleeve-like rubber lamination. 2. The structure defined in claim 1 and wherein said blade is characterized by two complete convolutions having a thick component situated midway between the respective ends of said shaft and complemental for- 20 wardly and rearwardly advancing components gradually decreasing in diameter toward and from the respective ends of said shaft, said blade having a ull-tur11convolution at the center and half-turn-convolutions at the ends and thus providing a structural adaptation which, 3 inside elevation, represents a double-pointed screw which lends itself to operation both forwardly and rearwardly with requisite thrust and stability in either direction while, at the same time, resisting fouling from debris and snags and yielding when encountering obstructions, whereby 30 to transmit required driving forces and torque while, at the same time, diminishing the likelihood of self-damage and breakage.

References Cited in the tile of this patent UNITED STATES PATENTS 930,409 Nielsen Aug. 10, 1909 2,087,243 Caldwell July 20, 1937 2,283,088 Peterson May 12, 1942 40 2,473,665 Van Nort June 21, 1949 FOREIGN PATENTS 17,054 Great Britain of 1897 121,589 Great Britain 1920 

